M.B.
I feel for you! Hang in there, it happened to me too and I know it's really tough. Try to get a family member or friend to take night duty for you so that you can have one good night's rest.
With my daughter, it was ear infections keeping her awake, and she didn't sleep really well until she got tubes at 8 mons. Make sure your doctor has ruled out everything like that and any weird rashes, or other things that might make him uncomfortable.
I'd also recommend something to make white noise, a fan helped with my daughter and her humidifier hums too. Also, if you can elevate one end the mattress in the crib a bit, maybe by slipping a rolled up blanket under one side and putting his head more upright, that helps with drainage if anything along those lines is bothering him.
But a night off for you is the best medicine...maybe as a suggested gift over the holidays?? :)
Best of luck!
M.